[Issue 21106] New: Add type inference for constructor calls

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21106

          Issue ID: 21106
           Summary: Add type inference for constructor calls
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: dlang.org
          Assignee: nobody at puremagic.com
          Reporter: porton at narod.ru

I propose to add type inference (similar to one for functions) for constructor
calls, that is to make the following program legal:

class C(T) {
  this(T) { }
}

void main() {
  immutable x = new C(0);
}

This would simplify programming eliminating the need to create a factory
function or factory functions for each template class.

Pro: shorter programs.

Con: some consider it a good practice to make a factory function ALWAYS.

Pro: even if you create a factory function, the body of this function itself
would be shortened.

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